Role of calcium in cholinergic and adrenergic mechanisms of eccrine sweat secretion.
The role of Ca2+ in eccrine sweat secretion was studied using isolated cannulated monkey palm eccrine sweat glands in vitro. Removal of Ca2+ from the incubation medium promptly abolished sweat secretion induced by methacholine or phenylephrine. In contrast, isoproterenol-induced sweat secretion lasted from 40 to 220 min in a Ca2+-free medium. The methacholine-induced maximal sweat rate was a hyperbolic function of the Ca2+ concentration in the bath and reached a plateau at 1 mM Ca2+. Higher Ca2+ concentrations rather suppressed the secretory rate. The Ca2+ ionophore A23187, but not X537A, at 3 X 10(-6) M induced copious prolonged sweat secretion after a latent period of 10 min. A23187-induced sweat secretion was not inhibited by either atropine or propranolol. D 600 (methoxyverapamil) at 10(-3) M inhibited sweat secretion induced by methacholine or by isoproterenol, although the latter lasted longer than methacholine sweating (20 vs. 5 min) in the presence of D 600. The data support the notion that Ca2+ influx into the cell plays a crucial role in cholinergic and alpha-adrenergic sweating, whereas a partial supply of Ca2+ for isoproterenol-induced sweating is derived from an intracellular store.
D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology*; D004439:Eccrine Glands / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D007832:Lasalocid / Q000494:pharmacology; D008253:Macaca mulatta; D016210:Methacholine Chloride; D008688:Methacholine Compounds / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D013542:Sweat / Q000187:drug effects / Q000378:metabolism*; D013545:Sweat Glands / Q000378:metabolism*
D008688:Methacholine Compounds; D016210:Methacholine Chloride; D010656:Phenylephrine; D000001:Calcimycin; D002118:Calcium; D007832:Lasalocid